Dr. Miller and Dr. Beebe have long been involved in original research on the health effects of the atomic bombing of Hiroshima and Nagasaki in 1945. Presently, with Dr. Land and colleagues at the Radiation Effects Research Foundation, Dr. Beebe is engaged in a study of primary cancer of the liver among A-bomb survivors in Japan. There is very little information on the effect of gamma and neutron radiation on the liver, whereas alpha radiation from the radiographic contrast medium, Thorotrast, is well known to induce liver cancer. Both Dr. Miller and Dr. Beebe make considerable use of data from the Japanese experience in consultations, lectures, and articles on radiogenic cancer. Dr. Beebe also plays a major role in the design of studies of leukemia and thyroid cancer following the 1986 Chernobyl accident in Ukraine. Chernobyl research is directed by Dr. Wachholz, Chief, Radiation Effects Branch, NCI. Scientific issues include: the biologic basis for variation in individual sensitivity to the carcinogenic influence of radiation, thyroid cancer in children from radioiodine exposure, high- vs low- linear-energy transfer (LET) in the induction of liver cancer, possible interaction between hepatic viruses and radiation in producing liver cancer, time-response characteristics of radiogenic cancers, and the influence of dose-rate and dose-fractionation on risk. Dr. Beebe is the Departmental Representative on the Science Panel of the Committee on Interagency Research and Policy Coordination under the newly organized National Science and Technology Council, and has been especially concerned with achieving a Federal consensus on risk estimates.